As is well known to those skilled in the art, middle distillate fuels typified by diesel fuel, home heating oil, etc are characterized by undesirable storage stability when stored in the presence of air even at room temperature. Over the course of time, these fuels become cloudy and produce sediment which deposits on the surfaces with which the fuel comes into contact. It particularly deposits on and clogs small openings such as those in fuel filters and strainers, in diesel engine injection nozzles, etc. It is an object of this invention to provide a middle distillate fuel oil characterized by improved storage stability. Other objects will be apparent to those skilled in the art.